1. Field of the Invention
The present invention relates to a probe card that senses the output of a magnetic sensor in a chip.
2. Description of the Prior Art
To date, a technique has been known in which a test on a test subject is carried out, by utilizing magnetic force (e.g., refer to Japanese Patent Application Laid-Open No. 11-237368).
Meanwhile, a semiconductor device equipped with a magnetic sensor is known. In the magnetic sensor, a magnetic-field sensing section that receives magnetic force and creates an output in accordance with the magnetic force, and a magnetic-sensor terminal for externally sensing the output created in the magnetic-field sensing section are provided. In a fabrication process for a semiconductor device equipped with a magnetic sensor, a test apparatus is utilized with which, being kept mounted on a wafer, the magnetic sensor incorporated in a chip on the wafer undergoes a test on its characteristics. In the test apparatus, by testing characteristics of a magnetic sensor, whether or not the quality of a chip is good is determined.
FIG. 5 is a view illustrating the configuration of a test apparatus, as an example of a conventional apparatus, with which characteristics of a magnetic sensor on a semiconductor device are tested.
In a test apparatus 50, a prober 51 is provided with which, before being cut as a chip, a semiconductor device is tested in the state of a wafer.
In the prober 51, a wafer platform 52 is provided; a wafer 53 is placed on a given position of the wafer platform 52. The wafer platform 52 is driven in X, Y, or Z direction by a driving device (unillustrated).
In addition, in the prober 51, a probe card 54 is provided that has probe pins 55 for contacting respective magnetic-sensor terminals (unillustrated) of subject chips and sensing respective outputs that are outputted at the magnetic-sensor terminals. Above the probe card 54, a magnetic-field generation device 60 is provided that applies magnetic force to a magnetic-field sensing section (unillustrated) on a chip. An electromagnet 63 is formed of an iron core 61 and a coil 62 wound around the iron core 61; an electromagnet-driving power source 64 is turned on, and a current flows in the coil 62, whereby the electromagnet 63 creates a magnetic field. The magnetic field leaks through the gap of the electromagnet 63; the leakage magnetic field is applied to the magnetic-field sensing section (unillustrated) on the chip. When the magnetic field is applied to the magnetic-field sensing section on the chip, the output of the magnetic-field sensing section varies in accordance with the magnetic force. Thus, the probe pin 55 contacts the magnetic-sensor terminal that is electrically connected to the magnetic-field sensing section, thereby sensing the output that is outputted at the magnetic-sensor terminal. A measurement section 65 measures, through a conducting wire 66, the output at the magnetic-sensor terminal, that has been sensed by the probe pin 55, and determines whether or not the chip quality is good, based on the result of the measurement.
In the conventional test apparatus 50, in order to, with the front-end positions of the probe pins 55 being regarded as reference, adjust the distance between the front-end positions of the probe pins 55 and the gap section of the electromagnet 63, a positioning mechanism (unillustrated) is provided with which the electromagnet 63 is moved vertically.
Moreover, in the conventional test apparatus 50, a large-size electromagnet is provided so that the magnetic field is widely created; however, due to the restriction that the electromagnet is arranged outside the prober 51, the distance between the front-end positions of the probe pins 55 and the gap section of the electromagnet is elongated, whereby it has been a problem that desired magnetic force may not be obtained.
Still moreover, use of a large-size electromagnet has an advantage in that, by widening the gap section of the electromagnet, the magnetic field can widely be homogenized; however, in some cases, it is required to apply the magnetic field locally to the magnetic-field sensing section of the magnetic sensor. Furthermore, in the case where an electromagnet that creates a high magnetic field is utilized, the increase of the frequency of the drive current results in large attenuation, due to the high inductance of the coil; because, in order to compensate the attenuation, a voltage is required to exceed several hundred volts, a commercially available power source cannot be utilized, thereby causing a problem of high cost.